Selective Protection and Deprotection of ortho-Functionalized Arylphosphonates

Abstract

Functionalized aromatic alkylphosphonates, hemi-phosphonates and phosphonic acids are good candidates to elaborate water-soluble building blocks. The key step of the synthesis developed here consisted of the introduction of a phosphoryl group by an ortho-metallation reaction from protected ortho-anisidine. A practical route to phosphonated benzoxazoles was thus discovered. Chemoselective deprotections were investigated and mono-, bis-, and ter-deprotected aromatic derivatives were obtained. © Georg Thieme Verlag Stuttgart. New York.